Field of the Invention
The present invention relates to a method and a device for the generative or additive manufacture of components by layer-by-layer joining of powder particles to one another and/or to an already produced semi-finished product or pre-product or substrate, via selective interaction of the powder particles with a high-energy beam, in particular a method and a device for selective laser-beam or electron-beam melting.
Prior Art
Additive manufacturing methods for the manufacture of a component, such as, for example, selective laser melting, selective electron-beam melting, or laser deposition welding, in which the component is built up layer-by-layer with the use of powder material, are employed in industry for so-called rapid tooling, rapid prototyping, or also for the production of mass-produced products within the scope of rapid manufacturing. In particular, such methods can also be used for the manufacture of turbine parts, particularly parts for aircraft engines, in which, for example, additive manufacturing methods of this type are advantageous due to the material used. An example of this is found in DE 10 2010 050 531 A1.
For improving such a method, it is known, for example, from WO 2012/152259 A1 to rework the applied layers or material layers after the melting and re-solidifying of the powder so as to influence the microstructure of the deposited material. This can be carried out, for example, by an ultrasonic impact treatment (UIT) or by a laser shock peening (LSP).
In the case of additive manufacture with a layer-by-layer application of material, surface roughness and the formation of defect sites in the form of pores and microcracks may occur at the edges of the deposited material layers, which may be an inner-lying surface (cavities) or an outer-lying (outside) surface of the component being produced.
In order to avoid these defect sites, it is known to post-weld the edge regions of the deposited material layers, i.e., to once more re-melt them in order to obtain an edge region that is as smooth as possible. Moreover, the surface of the component being produced can be smoothed by grinding or polishing in order to avoid the circumstance that there will be negative effects on strength, in particular resistance to vibration due to the surface roughness and defect sites in the surface.
Of course, in addition, there results the problem that the surfaces of the additively or generatively manufactured component are frequently not accessible or no longer accessible or difficultly accessible to the post-processing tools, in particular when they involve inner-lying surfaces of cavities. Additionally, a post-processing of the surfaces by grinding and polishing is often complex and costly, in particular when there needs to be a large amount of material removed in order to eliminate defect sites such as pores or microcracks in the surface or in regions near the surface.